windows 8. >> it really is an exciting, exciting day. windows 8, yeah, i'm excited. >> the biggest windows upgrade in 17 years went on sale around the world at the stroke of midnight. shoppers counted down to the launch. the operating system displayed square icons called tiles that provide touch screen functions. engineers designed the feature with tablet computers in mind. new pc models will have screens that can be separated from their keyboard and used as tablet devices. they hope the launch of windows 8 will boost sales.